Wireless signaling system.



1%;712766. PATENTED JAN. 6, 1903.

H. SHOEMAKER.

WIRELESS SIGNALING SYSTEM.

APPLIUATION FILED DEC 7, 1901.

K0 MODEL.

76M? QM, ig-m-ug mto'c M MM UNITED STATES PATENT OFFICE HARRY SHOEMAKER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR, BY

DIRECT AND MESNE ASSIGNMENTS,

PENNSYLVANIA, AND THE CONSOLIDATED WIRELESS TELE- DELPHIA,

GRAPH AND TELEPHONE OOMPAN RITORY.

of Letters Patent No. 717,766, dated January 6, 1903-.

SPECIFICATION forming part TO GUSTAVE P. GEHRING,,OF PHILA- Y, A CORPORATION OF ARIZONA TER- WiRELE SS SIG NALING SYSTEM.

Application filed December 7, 1901. Serial No. 84,996. (No model.)

To all whom it may concern:

Be it known that I, HARRY SHOEMAKER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and 5 State of Pennsylvania, have invented certain new and useful Improvements in Wireless Signaling Systems, of which the following is a specification.

My invention relates to electrical signaling,

re and more particularly to that class in which there are no artificial conductors connecting the transmitter and receiver.

It comprises also means for generating'electrical impulses and impressing them upon a medium and means for making manifest the impressed impulses at a receiver.

More specifically, it relates to an improvement in the receiving-circuits of wireless signaling systems, in which the relative movezo ment otthe elements of an electrostatic receiver is communicated to microphonic contacts included in the recorder-circuit, the object being to amplify the received impulses and make them more pronounced by calling 2 5 into action a local source of energy.

Reference is to be had to the accompanying sheet of drawings, in which- Figure I represents the transmitting apparatus, and Figs. II, III, and IV various forms of the receiver. Fig. V illustrates a restraining device connected between the earth-conductor of a receiver and the earth side of the charging-battery.

S is the secondary of a transformer in cir- 3 5 cuit with whose primary P is the key it; battery B, and, if desired, an interrupter of any of the usual types employed with inductioncoils. The secondary terminals are connected to earth-plates c 6 through the condensers K 0 K. The manipulation of the key is in accordance with a code will cause the impression upon the earth of a series of impulses which will radiate from the transmitter to the receiving devices.

The condensers K K are high-potential condensers of small capacity, whose function is to prevent the short-circuiting of the secondary coil through the earth between the two plates 6 6.

Only one such condenser is necessary, and in consequence condenser K may be short-circuited by the switch 3.

The nature of the energy transmitted is principally electrostatic, though there may be some slight component of electromagnetic. It is to be noted also that one earth connection 8 may be omitted and the corresponding terminal of the secondary connected to some other capacity area not connected to earth, as shown in dotted lines on Fig. I.

As-an alternative to the key signaling-circuit may be used the telephonic signalingcircuit, which comprises with the primary of the transformer the telephone-transmitter 2?, switch 5, and battery B. When the switch 5 is closed, the variation of current through the primary of the coil, due to the variation in pressure between the microphonic contacts of the transmitter, will cause an impression upon the transmitting medium of electrostatic stresses corresponding to such primary undulations.

In Fig. III is shown a simple form of receiving device which comprises two elements E E, of which E is fixed, while the member E is free to move to some extent in response to the attraction or repulsion between the two elements E E, due to electrostatic charges upon them. These two members are pretenably in the form of diaphragms placed close together and forming a condenser with air for dielectric. Bridging the two members is the high-potential battery B", whose purpose is to keep the members constantly charged,the advantage being the same as in the case of an ordinary telephonic receiver where the core is a permanent magnet. The plate E is connected to earth-plate e. f is an electrical and mechanical connection between the element E and the microphonic contacts 0. These microphonic contacts may comprise two carbon buttons or any of the well-known microphonic transmitters used in telephony.

In circuit with the microphone is the battery B and the telephone-receiver T, the complete circuit extending from battery B 5 through telephone receiver T to plate E through contact 0 back to battery.

The operation of the receiver is as follows:

The connection to earth-plate e transmits to the member E the electrostatic or other undulations impressed upon the transmitting medium at the transmitter. Such electrostatic charge either weakens or strengthens the charge already existing upon the plates E E and causes either a separation or an approach of the two members E E, and such relative motion changes the contact-pressure in the microphone, which in turn causes a rise and fall in the resistance of the telephone-circuit, such change of resistance being made manifest by current undulations in the telephone-receiver T.

In Fig. II, I have shown two pairs of diaphragms at E E and F F, each pair operating the microphones c c, which are joinedin series with each other and the battery B and telephone T. As in the previous case the high-potential battery B" keeps the plates E E F F constantly charged. By this arrangement very slight relative movement of the diaphragms is made manifest in the local circuit, due to the combined changes of resistance of the microphones c c, which, as stated above, are in series with each other and the local source of energy and the local recorder.

In Fig. IV are again shown two pairs of plates, Which are operated upon electrostatically and which control the two microphones c c,which in this case are connected in parallel and in series with battery B and telephone T. High-potential battery B permanently charges both pairs of plates E E and FF. The operation is the same as given in connection with Fig. III above.

In place of the transformer shown in Fig. I may be used any other high-potential generator of electricity, and in place of the forms of transmitters shown in the primary circuit may be used any equivalents, many of which are well known in the electrical arts.

In place of the microphonic contacts shown in the receiver circuits may be used any equivalent device which will cause a change of resistance in the local circuit proportionate to the movement of the receiver-diaphragmsEE.

In place of telephone-receiver T may be used any electroresponsive device which will produce either visible or audible indications, and in place of battery B may be used any high-potential source of energy, though preferably of a direct-current type. It, is desirable also in case of high-frequency undulations being used in the transmission to connect between the earth-wire and the pole of the battery B, which is shown in the various figures as connected directly to such earth-wire, some means, such as highresistance or an inductance-device, which will prevent the undulations from running into said batteryB, which has a relatively large electrostatic capacity and would in consequence prevent a maximum effect between the diaphragms E E. in Fig. V, where L represents a choke-coil or This arrangement is shown other suitable restraining device connected between the earth-conductor and. the earth side of the charging-battery B.

What I claim as new, and desire to secure by Letters Patent, is-

1. A receiver which comprises a plurality of plates in inductive relation, means for permanently charging said plates, and a microphonic circuit controlled by said plates.

2. A receiver which comprises a plurality of plates in inductive relation, a source of highpotential energy connected to opposing plates to charge them, and a local microphonic circuit controlled by said plates.

3. A receiver which comprises a plurality of plates in inductive relation, means for normally charging said plates and a local microphonic circuit including a telephone-receiver controlled by the relative movement of said plates.

4. A receiver which comprises a conductor in communication with the earth, a second conductor opposing said conductor, means for charging said conductors, and a microphonic circuit controlled by the relative movement of said conductors upon the reception of a signal.

5. The combination ofa plurality of pairs of plates in juxtaposition to each other, corresponding members of each pair being connected to earth, the remaining members controlling microphonic contacts connected in parallel; and a circuit including said microphonic contacts, a source of energy, and a recording device.

(3. The combination of aplurality of pairs of plates in juxtaposition to each other; an electrical connection from corresponding members of each pair to earth and to one pole of a high-potential source of current, the remaining members of each pair electrically connected together and to the remaining pole of the high-potential source of current; microphonic contacts electrically and mechanically connected to the last-named members of each pair, said microphonic contacts connected in parallel with each other; and a circuit including said contacts, a source of energy, and a recording device.

7. In an electric signaling system, the combination of a transmitter of electrostatic impulses; connections from said transmitter to earth; a receiver comprising a plurality of pairs of plates in juxtaposition to each other; electrical connections from corresponding members of each pair to earth and to one pole of a high-potential source of electricity, the remaining members of each pair connected to the remaining pole of said high -potential source; and microphonic means connected in parallel with each other operated upon by said remaining members of each pair; and an electric circuit including said contacts, a source of energy, and a recording device.

8. A receiver which comprises plates in inductive relation, an earth connection, means for charging said plates, microphonic contacts operated by the relative movement of said plates, and a signal-recording circuit including said microphonic contacts.

9. A receiver comprising plates in inductive relation, means for charging said plates, an earth connection whereby the charge on said plates may be varied in accordance with a transmitted signal, microphonic contacts controlled by said plates, and asignal-recording 1o circuit including said microphonic contacts.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HARRY SHOEMAKER.

Witnesses:

J. M. SAWYER, L. T. RHOADES. 

